Five-toed cattle once walked the earth…
Scientists at the University of Basel have identified a gene regulatory switch that was key to evolutionary adaption of limbs in ungulates, a category of animals that includes cattle and pigs. “The fossil record shows that all animals with four limbs originally had five toes (digits),” said Carol Wicking of the University of Queensland, who took part in the study. About 55 million years ago, ungulates developed an even number of toes, or in the case of cattle, cloven hooves.